AB0819 CLINICAL AND IMMUNOLOGICAL PROFILES OF PATIENTS WITH ANTI-SYNTHETASE SYNDROME: A RETROSPECTIVE COHORT STUDY FROM A TERTIARY CENTRE
Authors: O. M. Resteu, L. Muntean, D. A. Vaida-Voevod, A. Marian, S. P. Simon, I. Filipescu, M. M. Tamas, C. Pamfil, I. Szabo, L. Damian, I. Felea, S. Rednic
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Anti-synthetase syndrome (ASS) is a rare auto-immune condition that combines autoantibodies and specifics clinical manifestations, including myositis, interstitial lung disease (ILD), polyarthritis, mechanic's hands, Raynaud's phenomenon, and unexplained fever. The hallmark of this syndrome is the presence of anti-aminoacyl-tRNA-synthetase (ARS) antibodies. Several anti-ARS antibodies have been described, anti-Jo1 being the most common, followed by anti-PL7, anti-PL12, anti-OJ, anti-EJ, anti-KS, anti-YRS, and anti-Zo. According to a recent epidemiological survey, the rising number of patients with autoimmune diseases, including idiopathic inflammatory myopathies (IIM) coincides with the COVID-19 pandemic. <h3>Objectives</h3> To evaluate the clinical characteristics of ASS patients with different anti-ARS antibodies from a tertiary rheumatology center. <h3>Methods</h3> We conducted a retrospective, single-centered study on consecutive patients diagnosed with ASS from 1 January 2015 to 31 December 2022. Clinical and serologic data were obtained by medical records review from hospital database. Myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) were tested using commercial ELISA kits. We included all patients fulfilling Connor's criteria for ASS. <h3>Results</h3> Sixty-one patients (44 females) with mean age 54.4 (13.8) years were included. The most frequently reported clinical manifestation was arthralgia (68.8%), followed by Raynaud's phenomenon (67.2%), ILD (65.6%), myositis (46%), mechanic's hands (44.3%), arthritis (39.3%), and fever (18.0%). The typical triad for ASS, including myositis, arthritis and ILD was present in 17 patients. Twenty-eight (45.9%) patients were PL7+, 21 (34.4%) were Jo1+, 3 (4.9%) were PL12+, and 2 (3.2%) were OJ+. Seven patients were positive for more than two anti-ARS antibodies. The most frequently found MAA was anti-Ro52 (n=23, 37.7%). Of the 61 patients included, 41 (67.2%) patients were diagnosed in the last 3 years (COVID-19 pandemic). The most frequently detected MSA in ASS patients diagnosed during COVID-19 pandemic was anti-PL7 (25/28), while anti-Jo1 was the most common MSA in ASS patients diagnosed before 2020 (p&lt;0.05) (Fig 1). The anti-Jo1+ patients were younger, have significantly more frequent muscle involvement and significantly higher levels of CK than anti-PL7+ patients (p&lt;0.05). The co-occurance of anti-Ro52 antibodies was more frequently observed in anti-Jo1+ patients (n=11, 52.4%) than in anti-PL7+ patients (n=6, 21.4%) (p&lt;0.05). We did not find statistically significant differences between ASS groups regarding sex, disease duration, clinical manifestations including dermatologic lesions, Raynaud's phenomenon, arthralgia/arthritis, ILD, fever, and cancers (all p&gt;0.05). <h3>Conclusion</h3> ASS patients have heterogenous manifestations, and different types of anti-ARS antibodies are associated to distinct clinical and immunological features. The COVID-19 pandemic led to increase prevalence of ASS cases and to a remarkable shift in the anti-ARS antibodies profile, with increased frequency of anti-PL7 antibodies. Further studies are needed to investigate the link between SARS-CoV-2 infections and myositis. <h3>References</h3> [1]Witt LJ, et al. The Diagnosis and Treatment of Antisynthetase Syndrome. Clin Pulm Med. 2016 Sep;23(5):218-226. [2]Gracia-Ramos AE, et al. New Onset of Autoimmune Diseases Following COVID-19 Diagnosis. Cells. 2021 Dec 20;10(12):3592. [3]Connors GR, et al. Interstitial lung disease associated with the idiopathic inflammatory myopathies: what progress has been made in the past 35 years? Chest. 2010 Dec;138(6):1464-74. [4]García-Bravo Let al. Association of anti-SARS-COV-2 vaccine with increased incidence of myositis-related anti-RNA-synthetases auto-antibodies. J Transl Autoimmun. 2022 Jun 30;5:100160. <h3>Acknowledgements</h3> I have no acknowledgements to declare. <h3>Disclosure of Interests</h3> None Declared.